It is important to know at any age!

The Face Behind The Veil. Titan is a little larger than Mercury--the smallest major planet inhabiting our Solar System. Indeed, Titan would have been classified as a major planet in its own right if it orbited our Sun instead of Saturn. The Huygens Probe images lifted the veil from the face of this distant moon-world, revealing a youthful surface that is both smooth and relatively free of impact craters. Huygens also found that this icy, hydrocarbon-saturated moon's climate includes those heavy rains of gasoline, as well as raging, roaring winds. Some of Titan's surface features were found to be hauntingly akin to certain surface features on Earth.

and here is another

Ganymede: Ganymede is both the largest moon of Jupiter, our Solar System's planetary behemoth, as well as the largest moon in our entire Solar system. Observations of Ganymede by the HST in 2015 suggested the existence of a subsurface saline ocean. This is because patterns in auroral belts and rocking of the magnetic field hinted at the presence of an ocean. It is estimated to be approximately 100 kilometers deep with a surface situated below a crust of 150 kilometers.

and finally

For all its romance inspiring awesomeness, the moon has another side to its personality. Werewolves, mood swings and even wild behavior are often blamed on the full moon. How many times have you heard the question acrimoniously asked, "is it a full moon tonight?"

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Titan's atmosphere is approximately 95% nitrogen. However, in a way that dramatically differs from Earth's own mostly-nitrogen atmosphere, Titan's atmosphere has very little oxygen. Indeed, the remainder of Titan's atmosphere is almost entirely composed of methane--along with small qunatities of other gases, such as ethane. At the extremely cold temperatures that are found at Saturn's great distance from the heat of our Star, Titan's methane and ethane can accumulate on its icy surface to form pools of liquid.

The astronomers observed this effect in the upper layer of the lunar crust, termed the megaregolith. This layer is heavily pockmarked by relatively small craters, measuring only 30 kilometers or less in diameter. In contrast, the deeper layers of lunar crust, that are scarred by larger craters, appear not to have been as badly battered, and are, therefore, less porous and fractured.

"The whole process of generating porous space within planetary crusts is critically important in understanding how water gets into the subsurface. On Earth, we believe that life may have evolved somewhat in the subsurface, and this is a primary mechanism to create subsurface pockets and void spaces, and really drives a lot of the rates at which these processes happen. The Moon is a really ideal place to study this," Dr. Soderblom explained in the MIT Press Release.